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| author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2014-08-02 08:43:31 +0200 |
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| committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2014-08-02 08:43:31 +0200 |
| commit | daf17154bf13139d9375f48525d19d6aaba08155 (patch) | |
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diff --git a/html/xbc13.htm b/html/xbc13.htm new file mode 100755 index 0000000..e085157 --- /dev/null +++ b/html/xbc13.htm @@ -0,0 +1,470 @@ +<!DOCTYPE HTML PUBLIC> +<HTML> +<TITLE>Xbase DBMS Chapter 13</TITLE> +<BODY BGCOLOR=#FFFFFF> +<H1><p align="center">Field Methods</p></H1> +<p align="center">Chapter Updated 2/1/99</p><hr> + +This chapter lists the field methods and provides examples of how to use +them.<br><br> + +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Xbase Field Method List</h3></CAPTION> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Method<TD>Description +<TR><TH ALIGN="LEFT">xbLong cnt FieldCount()<TD>Returns the number of fields + in the file +<TR><TH ALIGN="LEFT">xbDouble d GetDoubleField(char * FieldName)<TD>Returns a xbDouble field for field name +<TR><TH ALIGN="LEFT">xbDouble d GetDoubleField(xbShort FieldNo)<TD>Returns a xbDouble field for field number +<TR><TH ALIGN="LEFT">xbShort rc GetField(xbShort,char *buf)<TD>Gets field data from the record buffer +<TR><TH ALIGN="LEFT">xbShort d GetFieldDecimal(xbShort FieldNo)<TD>Gets field decimal count +<TR><TH ALIGN="LEFT">xbShort len GetFieldLen(xbShort FieldNo)<TD>Returns the length of a given field +<TR><TH ALIGN="LEFT">char * name GetFieldName(xbShort FieldNo)<TD>Returns field name for field number +<TR><TH ALIGN="LEFT">xbShort FieldNo GetFieldNo(char * FieldName)<TD>Returns the field ID number for a given field +<TR><TH ALIGN="LEFT">char type GetFieldType(xbShort FieldNo)<TD>Returns the type of a given field +<TR><TH ALIGN="LEFT">xbFloat f GetFloatField(char * FieldName)<TD>Returns a float field for field name +<TR><TH ALIGN="LEFT">xbFloat f GetFloatField(xbShort FieldNo)<TD>Returns a float field for field number +<TR><TH ALIGN="LEFT">xbShort l GetLogicalField(xbShort FieldNo)<TD>Returns logical field data +<TR><TH ALIGN="LEFT">xbShort l GetLogicalField(char * FieldName)<TD>Returns logical field data +<TR><TH ALIGN="LEFT">xbLong l GetLongField(char * FieldName)<TD>Returns a long field for field name +<TR><TH ALIGN="LEFT">xbLong l GetLongField(xbShort FieldNo)<TD>Returns a long field for field number +<TR><TH ALIGN="LEFT">xbShort rc GetMemoField(xbShort FieldNo,<br>xbLong len,char * buf)<TD>Get memo field data +<TR><TH ALIGN="LEFT">xbLong len GetMemoFieldLen(xbShort FieldNo)<TD>Get memo field data length +<TR><TH ALIGN="LEFT">xbShort s MemoFieldsPresent()<TD>Determine if memo fields exist in DBF file +<TR><TH ALIGN="LEFT">xbShort s MemoFieldExists(xbShort FieldNo)<TD>Determine if a particular memo field has data +<TR><TH ALIGN="LEFT">xbShort rc PutDoubleField(char * FieldName,<br>xbDouble d)<TD>Updates a xbDouble field for field name +<TR><TH ALIGN="LEFT">xbShort rc PutDoubleField(xbShort FieldNo,<br>xbDouble d)<TD>Updates a xbDouble field for field number +<TR><TH ALIGN="LEFT">xbShort rc PutField(xbShort FieldNo,char * val)<TD>Fills or overlays a field in the current record buffer +</TABLE> + +<br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Xbase Field Method List (cont)</h3></CAPTION> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Method<TD>Description +<TR><TH ALIGN="LEFT">xbShort rc PutFloatField(char * FieldName,<br>xbFloat f)<TD>Updates a float field for field name +<TR><TH ALIGN="LEFT">xbShort rc PutFloatField(xbShort FieldNo,<br>xbFloat f)<TD>Updates a float field for field number +<TR><TH ALIGN="LEFT">xbShort rc PutLongField(char * FieldName,<br>xbLong l)<TD>Updates a long field for field name +<TR><TH ALIGN="LEFT">xbShort rc PutLongField(xbShort FieldNo,<br>xbLong l)<TD>Updates a long field for field number +<TR><TH ALIGN="LEFT">xbShort rc UpdateMemoData(xbShort FieldNo,<br>xbLong len,char * buf, +xbShort LockOpt)<TD>Update memo field data +<TR><TH ALIGN="LEFT">xbShort l ValidLogicalData( char * buf )<TD>Check for valid logical data +<TR><TH ALIGN="LEFT">xbShort l ValidNumericData( char * buf )<TD>Check for valid numeric data +</TABLE> +<BR><BR> + +<hr> +<h2>Method Definitions</h2> +<hr> + +<h3>Method xbLong xbDbf::FieldCount( void )</h3><br> +This method returns the number of fields which exist in the database. +<br><br> +<h4>Method Return Codes</h4><br> +If successful, this method returns the number of fields in the database. +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample3.cpp">sample3.cpp</A> for an +example of how to use this method. +<hr> + +<h3>Method xbDouble xbDbf::GetxbDoubleField( char * FieldNo )</h3><br> +This method returns a xbDouble value for field FieldNo. Fieldno can be retrieved +by using method GetFieldNo. +<br><br> +<hr> + +<h3>Method xbDouble xbDbf::GetxbDoubleField( char * FieldName )</h3><br> +This method returns a xbDouble value for field FieldName. If multiple accesses +for this particular field will be made from within the program, it is more +efficient to access the data utlizing the field's number, rather than its name. +<br><br> + +<hr> +<h3>Method xbShort xbDbf::GetField( xbShort FieldNo, char * buf )</h3><br> + +This method fills an application program supplied buffer *buf with data +from the record buffer for field number FieldNo. FieldNo can be retrieved +by using method GetFieldNo.<br><br> + +It is the responsibility of the application program to verify the buffer is +large enough to hold the data. No checking is done by method GetField to +verify the buffer is large enough to hold the data.<br><br> +If successful, this method returns the length of the field in bytes. + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample3.cpp">sample3.cpp</A> for an +example of how to use this method. + +<hr> +<h3>Method xbShort xbDbf::GetFieldDecimal( xbShort FieldNo )</h3><br> + +This method returns the decimal count of field FieldNo. FieldNo can be retrieved +by using method GetFieldNo.<br><br> +If successful, this method returns the decimal count. + +<hr> +<h3>Method xbShort xbDbf::GetFieldLen( xbShort FieldNo )</h3><br> + +This method returns the length of field FieldNo. FieldNo can be retrieved +by using method GetFieldNo.<br><br> +If successful, this method returns the length of the field in bytes. + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample3.cpp">sample3.cpp</A> for an example +of how to use this method. + +<hr> +<h3>Method char * xbDbf::GetFieldName( xbShort FieldNo )</h3><br> + +This method returns a pointer to the name of field FieldNo. FieldNo can be retrieved +by using method GetFieldNo.<br><br> +If successful, this method returns the field name.<br> + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/dumpdbt.cpp">dumpdbt.cpp</A> for an example +of how to use this method. +<hr> + +<h3>Method xbShort xbDbf::GetFieldNo( char * FieldName )</h3><br> + +This method is used to get a field's ID number based on paramater +FieldName. Where FieldName is a valid name of a field in the database.<br><br> + +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">-1<TD>Field not found in record +<TR><TH ALIGN="LEFT">0 through n<TD>The field number for field FieldName +</TABLE> +<br><br> +<h4>Example Program:</h4> + +See sample program <A HREF="/XbaseSamples/sample2.cpp">sample2.cpp</A> for an example +of how to use this method. + +<hr> +<h3>Method xbShort xbDbf::GetFieldType( xbShort FieldNo )</h3><br> + +This method returns the type of field FieldNo. FieldNo can be retrieved +by using method GetFieldNo.<br><br> + +<h4>Method Return Codes</h4><br> +If successful, this method returns the field type.<br> +C = character<br> +D = Date<br> +L = Logical<br> +M = Memo<br> +N = Numeric<br> +F = Float<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample3.cpp">sample3.cpp</A> for an example +of how to use this method. +<hr> + +<h3>Method xbFloat xbDbf::GetFloatField( char * FieldName )</h3><br> + +This method returns a float value for field FieldName. If multiple accesses +for this particular field will be made from within the program, it is more +efficient to access the data utlizing the field's number, rather than its name. +<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample3.cpp">sample3.cpp</A> for an +example of how to use this method. +<hr> +<h3>Method xbFloat xbDbf::GetFloatField( xbShort * FieldNo )</h3><br> + +This method returns a float value for field number FieldNo. +<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample3.cpp">sample3.cpp</A> for an +example of how to use this method. +<hr> + + +<h3>Method xbShort xbDbf::GetLogicalField( xbShort FieldNo )</h3><br> + +<h3>Method xbShort xbDbf::GetLogicalField( char * FieldName )</h3><br> + +This method returns -1 if field <em>FieldName</em> or <em>FieldNo</em> is not +a logical field. +It returns 1 if field <em>FieldName</em> is a 'T','t','Y' or 'y'. It returns +0 if not 'T','t','Y' or 'y'. +<br> +<hr> +<h3>Method xbLong xbDbf::GetLongField( xbShort * FieldNo )</h3><br> + +<h3>Method xbLong xbDbf::GetLongField( char * FieldName )</h3><br> + +This method returns a long value for field FieldName. If multiple accesses +for this particular field will be made from within the program, it is more +efficient to access the data utlizing the field's number, rather than its name. +<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/zips/zipinit.cpp">zipinit.cpp</A> for an +example of how to use this method. + +<hr> +<h3>Method xbLong xbDbf::GetLongField( xbShort * FieldNo )</h3><br> + +This method returns a long value for field FieldNo. FieldNo can be +determined by utilizing method GetFieldNo. +<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/zips/zipinq.cpp">zipinq.cpp</A> for an +example of how to use this method. + + + +<hr> +<h3>Method xbShort xbDbf::GetMemoField( xbShort FieldNo, xbLong len, char * Buf, xbShort LockOption )</h3><br> + +This method returns <em>Len</em> bytes of memo field <em>FieldNo</em>. <em>Buf</em> +is a user supplied buffer large enough to contain the data. No checking +of the field's size is performed by this method.<br><br> + + +<em>Lock Option</em>is one of:<br> + +F_SETLK - return immediately if lock fails<br> +F_SETLKW - wait until lock function executes<br><br> + +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_INVALID_FIELDNO<TD>An invalid field number was used +<TR><TH ALIGN="LEFT">XB_NOT_MEMO_FIELD<TD>Not a memo field +<TR><TH ALIGN="LEFT">XB_NO_MEMO_DATA<TD>No memo data exists +<TR><TH ALIGN="LEFT">XB_INVALID_BLOCK_NO<TD>Internal error, notify tech support +<TR><TH ALIGN="LEFT">XB_SEEK_ERROR<TD>Disk Error +<TR><TH ALIGN="LEFT">XB_READ_ERROR<TD>Disk Error +<TR><TH ALIGN="LEFT">XB_NO_ERROR<TD>No Error +</TABLE> +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/dumpdbt.cpp">dumpdbt.cpp</A> for +an example of how to use this method. + +<hr> +<h3>Method xbLong xbDbf::GetMemoFieldLen( xbShort FieldNo )</h3><br> + +This method returns the length of memo field FieldNo. FieldNo can be +retrieved by using method GetFieldNo.<br><br> +If successful, this method returns the length of the memo field in bytes. + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/dumpdbt.cpp">dumpdbt.cpp</A> for +an example of how to use this method. + +<hr> + +<h3>Method xbShort xbDbf::MemoFieldExists( xbShort FieldNo )</h3><br> + +This method returns true (1) if field FieldNo has any memo data. Otherwise +it returns false (0). +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">0<TD>Data file does not have any memo fields +<TR><TH ALIGN="LEFT">1<TD>Data file has memo fields +</TABLE> +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/dumpdbt.cpp">dumpdbt.cpp</A> for an +example of how to use this method. + +<hr> + +<h3>Method xbShort xbDbf::MemoFieldsPresent( void )</h3><br> + +This method returns true (1) if the file has any memo fields. Otherwise +it returns false (0). +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">0<TD>Data file does not have any memo fields +<TR><TH ALIGN="LEFT">1<TD>Data file has memo fields +</TABLE> +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/dumpdbt.cpp">dumpdbt.cpp</A> for an +example of how to use this method. + +<hr> +<h3>Method xbShort xbDbf::PutxbDoubleField( char * FieldName, xbDouble d )</h3><br> + +This method puts a xbDouble value d for field FieldName. If multiple accesses +for this particular field will be made from within the program, it is more +efficient to access the data utlizing the field's number. +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_INVALID_FIELDNO<TD>An invalid field number was used +<TR><TH ALIGN="LEFT">XB_INVALID_DATA<TD>Attempt to load invalid numeric or logical data +</TABLE> +<br><br><hr> +<h3>Method xbShort xbDbf::PutxbDoubleField( xbShort FieldNo, xbDouble d )</h3><br> +This method puts a xbDouble value d for field FieldNo. +<br><br> +<h3>Method Return Codes</h3> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_INVALID_FIELDNO<TD>An invalid field number was used +<TR><TH ALIGN="LEFT">XB_INVALID_DATA<TD>Attempt to load invalid numeric or logical data +</TABLE> +<br><br> + +<hr> +<h3>Method xbShort xbDbf::PutField( xbShort FieldNo, char * buf )</h3><br> + +This method fills field number FieldNo, with the data from buffer *buf.<br><br> +It copies data from *buf until a 0x00 character is encountered or the buffer +is filled. The field will be truncated if it is to long.<br><br> +Use method GetFieldNo to determine the value for FieldNo.<br><br> +If the field is type N or F, the field is loaded right justified, left blank +filled onto the record buffer.<br><br> +This method does check the validity of NUMERIC and LOGICAL data it is loading onto the +record buffer. Ther can be no spaces or non-numeric data for numeric fields.<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_INVALID_FIELDNO<TD>An invalid field number was used +<TR><TH ALIGN="LEFT">XB_INVALID_DATA<TD>Attempt to load invalid numeric or logical data +</TABLE> +<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample2.cpp">sample2.cpp</A> for an example +of how to use this method. +<hr> + +<h3>Method xbShort xbDbf::PutFloatField( char * FieldName, FLOAT f )</h3><br> + +This method puts a float value f for field FieldName. If multiple accesses +for this particular field will be made from within the program, it is more +efficient to access the data utlizing the field's number. +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_INVALID_FIELDNO<TD>An invalid field number was used +<TR><TH ALIGN="LEFT">XB_INVALID_DATA<TD>Attempt to load invalid numeric or logical data +</TABLE> +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample2.cpp">sample2.cpp</A> for an +example of how to use this method. +<hr> +<h3>Method xbShort xbDbf::PutFloatField( xbShort FieldNo, FLOAT f )</h3><br> +This method puts a float value f for field number FieldNo. +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_INVALID_FIELDNO<TD>An invalid field number was used +<TR><TH ALIGN="LEFT">XB_INVALID_DATA<TD>Attempt to load invalid numeric or logical data +</TABLE> +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample2.cpp">sample2.cpp</A> for an +example of how to use this method. +<hr> +<h3>Method xbLong xbDbf::PutLongField( char * FieldName, xbLong Val )</h3><br> +This method puts a long value Val for field FieldName. If multiple accesses +for this particular field will be made from within the program, it is more +efficient to access the data utlizing the field's number. +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/zips/zipinit.cpp">zipinit.cpp</A> for an +example of how to use this method. + +<hr> +<h3>Method xbLong xbDbf::PutLongField( xbShort FieldNo, xbLong Val )</h3><br> +This method puts a long value Val for field FieldNo. FieldNo can be determined +by utilizing method GetFieldNo. +<br><br> + +<h4>Example Program:</h4> +See sample program <A HREF="/zips/zipinq.cpp">zipinq.cpp</A> for an +example of how to use this method. +<hr> +<h3>Method xbShort xbDbf::UpdateMemoData( xbShort FieldNo, xbLong len, + char * Buf, xbShort LockOption )</h3><br> +This method updates field <em>FieldNo</em> with <em>Len</em> bytes of +data from <em>Buf</em>.<br><br> +This is the only routine necessary to add, revise or delete memo field +data. To delete a memo field, set the length to zero (0L).<br><br> + +<em>LockOption</em> is one of<br> +<li>F_SETLK - return immediately if lock fails +<li>F_SETLKW - wait until lock function executes +<br><br> + +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">XB_LOCK_FAILED<TD>Lock Failed +<TR><TH ALIGN="LEFT">XB_INVALID_BLOCK_NO<TD>Internal error, notify tech support +<TR><TH ALIGN="LEFT">XB_SEEK_ERROR<TD>Disk Error +<TR><TH ALIGN="LEFT">XB_READ_ERROR<TD>Disk Error +<TR><TH ALIGN="LEFT">XB_WRITE_ERROR<TD>Disk Error +<TR><TH ALIGN="LEFT">XB_NO_ERROR<TD>No Error +</TABLE> +<br><br> +<h4>Example Program:</h4> +See sample program <A HREF="/XbaseSamples/sample2.cpp">sample2.cpp</A> for +an example of how to use this method. +<hr> + + + +<h3>Method xbShort xbDbf::ValidLogicalData( char * data )</h3><br> + +This method returns true if <em>data</em> contains a valid logical data value. +Otherwise, it returns false. +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">1<TD>Valid logical data +<TR><TH ALIGN="LEFT">0<TD>Invalid logical data +</TABLE> +<br> +<hr> + +<h3>Method xbShort xbDbf::ValidNumericData( char * data )</h3><br> +This method returns true if <em>data</em> contains a valid numeric data value. +Otherwise, it returns false. +<br><br> +<TABLE BORDER> +<CAPTION ALIGN="TOP"><h3>Method Return Codes</h3></CAPTION><br> +<TR VALIGN="BASELINE"> +<TR><TH ALIGN="LEFT">Return Code<TD>Description +<TR><TH ALIGN="LEFT">1<TD>Valid numeric data +<TR><TH ALIGN="LEFT">0<TD>Invalid numeric data +</TABLE> +<br> +<hr> + +<p><img src="xbase.jpg"><br><hr> +</BODY> +</HTML> |